Yesterday], two days after the Melbourne international festival opened, hackers replaced programme information with the Chinese flag and anti-Kadeer slogans and sent spam emails in an attempt to crash the site, according to reports in the Australian press.

"We like film but we hate Rebiya Kadeer," one message said, demanding an apology to the Chinese people.

The festival director, Richard Moore, said staff had been bombarded with abusive emails after he rebuffed demands from the Chinese government to drop the film about Kadeer, The 10 Conditions of Love, and cancel her invitation to the festival.

"The language has been vile," Moore told the Melbourne Age. "It is obviously a concerted campaign to get us because we've refused to comply with the Chinese government's demands."

He said the festival had reported the attacks, which appear to be coming from a Chinese internet protocol address, and was discussing security concerns with Victoria's state police. Private security guards are being hired to protect Kadeer and other patrons at the film's screening on August 8.

Kadeer denies Beijing's claim that she masterminded this month's riots in Xinjiang's capital, Urumqi, in which almost 200 people died.The 10 Conditions of Love, directed by the Australian filmmaker Jeff Daniels, describes Kadeer's relationship with her activist husband Sidik Rouzi and reveals the impact of her campaign for more autonomy for China's 10 million mainly Muslim Uighurs on her 11 children, three of whom have received jail sentences.

Once one of the richest women in Xinjiang and held up as an exemplar of China's purported multi-ethnic harmony, Rebiya Kadeer now heads two prominent Uighur exile groups, speaking out against Beijing's oppression of the Turkic-speaking minority.

Kadeer's persecution by the Chinese and her stature as a public face of the Uighur people have earned her comparisons to the Dalai Lama, the exiled Tibetan spiritual leader. Like him, she has been an unrelenting target for Chinese opprobrium.

Her appearance at the Melbourne film festival means the event has also come into Chinese sights. Last week, three Chinese directors withdrew films, with two denying they were forced to do so by Chinese authorities. Director Tang Xiaobai, who withdrew her film Perfect Life after being phoned by the Chinese foreign ministry and the state administration of radio, film and television, said it was her decision to boycott the festival.

"I do not want to see my film screened on the same platform as a film about Kadeer," Tang told the official English-language newspaper China Daily.

The row over the Kadeer documentrary is not the only row to hit the festival. The British film director, Ken Loach, last week withdrew his film, Looking for Eric, in protest at its decision to accept sponsorship from Israel.